Re: 2nd attempt: Window function SQL - can't quite figure it.

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От David G. Johnston
Тема Re: 2nd attempt: Window function SQL - can't quite figure it.
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Msg-id CAKFQuwbfsy+2Z8WQXn6nyDQVpADwYje7LvAg5pWrP-R9t5OhnQ@mail.gmail.com
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Ответ на Re: 2nd attempt: Window function SQL - can't quite figure it.  (Pál Teleki <ellenallhatatlan@gmail.com>)
Ответы Re: 2nd attempt: Window function SQL - can't quite figure it.  (Pál Teleki <ellenallhatatlan@gmail.com>)
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On Monday, July 18, 2016, Pál Teleki <ellenallhatatlan@gmail.com> wrote:
Now, why can't I use deptot and stot_per_man aliases in  my query? It would
greatly simplify the SQL by removing the need for a subquery (or inline view
as Oracle calls them).

SQL execution of a query is only done once.  Referring to an alias at the same level in a query would require some kind of duplication to work.  Either two phase processing or cloning the subselect that is being alised and executing it a second time to be used in the second location.  Neither are desirable.

David J.

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